I should be able to log into these devices without having to add in the password each time, using the id_rsa file, but it keeps asking.

[MYNAME@vd-MYNAME scripts]$ ./ifc
Enter first SITE number: 1000
Enter last SITE number: 1000
The authenticity of host 'SITE1000-n1 (10.105.87.238)' can't be established.
RSA key fingerprint is f2:25:48:f0:97:f8:10:30:79:96:54:4f:22:cb:09:f8.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added 'SITE1000-n1,10.106.86.226' (RSA) to the list of known hosts.root@SITE1000-n1's password:

It was an issue with the id_rsa file for me. I used one from 2016 and it worked. I pointed my script to that file.
I did not need a .ssh folder or anything extra.
My script is simply this with the new file location of an old file I had early 2016.
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#!/bin/bash